They are special investigations into the backgrounds of nominees to the Supreme Court and other high profile jobs in any presidential administration.

Perhaps never before has such attention been focused on the long-shrouded process than in the case of Brett Kavanaugh.

And Friday brought a new and unexpected wrinkle: Republican senators and President Donald Trump acquiesced to Democrats’ demand for the re-opening of Kavanaugh’s background inquiry to vet allegations of sexual assault against the Supreme Court nominee leveled by high school acquaintance Christine Blasey Ford.

While an extraordinary Senate Judiciary Committee hearing did little to reconcile the dueling accounts offered by Ford and Kavanaugh, lawmakers now believe that a clearer picture of the nominee’s credibility would likely emerge and President Donald Trump Friday authorized a "limited" one-week FBI review.

Only the White House was authorized to re-open the background review, closed long before Ford’s allegations were made public. But even in the narrow amount of time provided by Trump, former FBI officials said agents could reach a quick resolution.

“They could knock this thing out in a couple of days,” said Jim Davis, a former agent who participated in at least 50 such background inquiries. “The great and beautiful thing about the FBI is that it can apply incredible resources to whatever the issue requires.”

Phil Mudd, a former CIA and FBI official who has been the subject of a half-dozen background checks, said such re-investigation is common and can be completed fairly quickly.

"You have to let things go where they go, but if it is narrow in scope it could take just a few days," Mudd said.

Apart from Ford, among the first witnesses likely to be contacted by investigators is Kavanaugh's high school friend, Mark Judge, who Ford claims was in the room when she was assaulted at a house party in the Washington, D.C. suburbs in 1982.

Ford told the Senate panel that while she was allegedly being assaulted by Kavanaugh, she made eye contact with Judge who she had hoped would come to her aid.

Democrats had unsuccessfully sought to have Judge testify at Thursday's hearing.

Judge, in a statement Friday, said he would "cooperate with any law enforcement agency that is assigned to confidentially investigate these allegations."

Judge had previously told the committee in a sworn statement that he had "no memory" of the incident outlined by Ford.

In her testimony, Ford identified two others who were allegedly present at the party, P.J. Smyth and Leland Ingham Keyser. Both of them also have issued statements indicating that they no recollection of the party.

Davis, the former FBI agent, said all of those identified as being present at the party would almost certainly be interviewed, as well the people who Ford told of the incident.

Prior to Thursday's hearing, Ford's attorneys provided the Senate committee with sworn declarations from four people, including Ford's husband, who said that Ford had shared details of the incident and Kavanaugh's alleged involvement with them.

Ford's husband, Russell Ford, said he first learned of his wife's experience with sexual assault "around the time we got married." However, he said Ford did not share details of the incident until a couple's therapy session in 2012.

"I remember her saying that her attacker's name was Brett Kavanaugh, that he was a successful lawyer who had grown up in Christine's hometown, and that he was well known in the Washington, D.C., community," Russell Ford said.

It was unclear whether the scope of an FBI inquiry would allow for the review of other allegations leveled by former Yale classmate, Deborah Ramirez, who claimed that Kavanaugh exposed himself at a drunken party during the 1983-84 academic year.

Another woman, Julie Swetnick, has alleged that in the 1980s she witnessed Kavanaugh and Judge attempt to ply teenage girls with alcohol at wild parties where girls were sexually abused.

She did not say Kavanaugh or Judge sexually assaulted her.

Kavanaugh has denied all of the allegations.

In his statement Friday, Judge said he did not recall attending the parties.

"The allegations in the Swetnick affidavit are so bizarre that, even while suffering from my addiction, I would remember actions so outlandish. I categorically deny them," he said.

Kavanaugh has said that Judge struggled with alcohol addiction.

"The FBI is going to put together a list, and you can bet that all of the people whose names have been floated out there are going to be on it," said Ray Mey, a former FBI agent who conducted dozens of background checks during his tenure at the bureau.

"The FBI has more than enough resources to do this in a week," he said. "What I worry about, is that nobody comes out of this looking good, including the FBI."

If the FBI discovers derogatory information, Mey said the FBI risks invoking the wrath of the president who has accused of the bureau of attempting to sabotage his administration as part of its inquiry into Russia's interference in the 2016 election.

"If they don't find anything, the other side will say it's a cover-up," Mey said. "Either way, the bureau doesn't gain anything."